[KC Jones]

Good stuff, but misses airspeed. True airspeed = altitude adjusted speed +- wind velocity which either makes you faster or slower relative to ground speed. Since you are trying to go somewhere, ground speed is what you want to know to see how "fast" you are going!

BTW, the internet is your friend.. there are a zillon different ways to answer most questions with a simple google search, and there are tons of math/unit converters...

Airspeed is not calculated using wind velocity only ground speed is affected by wind velocity.

Let me try to explain so you can understand. The aircraft once it becomes airborne is now operating in a large fluid namely air. Fluid speed ( windspeed )is a value we assign when this fluid is moving relative to a fixed point ( Me standing at a weather station). A good example is the fishbowl analogy. a fish is swimming around in his bowl of water ( substitute air for water ) at 2 knots through the water in a circle so his ground speed is almost nil. You pick up the fishbowl and start running at 15 knots for an hour( This is the windspeed). The fish is still swimming through his fluid at 2 knots no matter what direction he goes but his ground speed is 15 knots. Substitute an aircraft for the fish. Do you see yet. Yes the modern pitot static system works on ram air or dynamic pressure of the fluid into the forward facing opening but as far as the aircraft and its fluid that it is operating in it is always facing forward.

Egards ! See what you started PDelaney ! :roll:

I knew it was going to come down to this.

First Spinnetti, ..my last inserted picture is how you compute true airspeed (TAS). I should have so stated. Wind is not involved in computing it.

Your observation was about groundspeed. That is where wind (if any) is taken into account.

Congompasse, your explanation is "fishy" but good. :mrgreen:

I always believe a picture is worth a thousand mile journey.

Here's a couple of pictures about groundspeed and wind.

They may be over 20+ years old but are still valid. Here's a downloadable sample at http://www.rodmachado.com/Images/Privat ... 20Here.pdf






Computing true airspeed (TAS)



Download more samples from Rod's Private Pilot Handbook at

http://www.rodmachado.com/Product/Books ... cerpts.htm